1. Field of the Invention
The present invention relates to elongated frame members for use in curtain wall structures including a framework and one or more glazing panels. More particularly, the frame members of the present invention are adapted to provide a heat insulating thermal barrier between outside and inside elements of the framework and thereby reduce heat losses. The inside and outside elements of the frame members are formed of heat conductive extruded metal such as aluminum and the heat insulating thermal barrier is achieved by the use of rigid, heat insulating plastic resin material which structurally interconnects the inside and outside elements while providing a heat insulating thermal barrier therebetween. The frame members provide one or more glazing recesses for receiving marginal edge portions of glazing panels carried by a framework constructed of the frame members. The structural interconnection between the inside and outside elements of the frame members is designed so that these element are not likely to become detached even if the heat insulating material fails completely.
2. Description of the Prior Art
Because of the increasing costs of energy and a desire for reducing the heat loss through structural frame elements used for supporting glazing panels and the like, a variety of construction is disclosed and claimed in U.S. Pat. No. 3,204,324, issued Sept. 7, 1965. Another type of insulating frame member is disclosed in U.S. Pat. No. 3,729,354, issued Apr. 24, 1973 which patent is assigned to the same Assignee as the present application.